Machines such as excavators, backhoe loaders and the like typically employ a implement system or assembly comprised of one or more controllably articulable arms extending from a base or frame and other additional components that are pivotably attached to a distal portion of one or more of the arms such as a bucket and thumb. Such individual components are typically very heavy in weight in and of themselves and must be adjusted to one or more fixed positions to perform intended operations. Due to their weight, such components may not capable of being manually adjustable by one person to the one or more fixed pivot positions. U.S. Pat. Nos. 6,120,237 and 6,354,790 disclose machines having assemblies on which such a heavy thumb member is pivotably attached. The thumb member is movable to selected pivot positions relative to other components of the assembly by a drive system operated remotely by a user sitting in a cab.